It doesn't use $this, except to call getWikiTitle(), so make that
static too. This allows us to use it in EchoForeignPresentationModel
without creating a second instance there.
Change-Id: If778db0852de1cbf5c2190ce50ce561745bb3887
Using wiki names in the header is problematic because the messages
we were using weren't designed to be used in a sentence, only in headings.
This removes the wiki names from the sentence in the header, and
instead puts a comma-separated list (with "and") of wikis in the body.
The messages keep $3 and $4 for backwards compatibility, so translations
of the form "from Commons and 2 other wikis" will keep working.
Bug: T121936
Change-Id: Ideeba794e260b3c388fa29226b53197c050162ef
